Trimmer for sewing-machines



(No Model.)

T. K. OBER.

TRIMMER FOR SEWING MAGHINES.

No. 323,439. Patented Aug. 4, 1885.

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THOMAS K. OBER, OF PHILADELPHIA, PENNSYLVANIA.

TRIMMER FOR SEWlNG-MACHINES.

SPECIFICATION forming part of Letters Patent No, 323,439, dated August 4, 1885.

Application tiled March 23, 1885. (No model.)

To all whom it may concern:

Be it known that I, THOMAS K. OBER, of: the city and county of Philadelphia, and State of Pennsylvania, have invented an Improvement in Trimmers for SewingMachines, of i which the following is aspccitication.

My invention has reference to trimming devices for sewing-machines; and it consists in certain improvements upon Letters Patent No. 303,818, to E. D. Cummings, dated August 19, 1884, by which the reciprocating cutter is kept in a sharpened condition, which are fully set forth in the following specification, and shown in the accompanying drawings, which form part thereof.

The object of this invention is to provide suitable means by which the cuttingedge of the reciprocating knife or cutter may be maintained in a sharpened condition by its automatic action upon the sharpening-stone, suitably supported or carried in the throat-plate or equivalent part of the sewingmachine.

In the drawings, Figure 1 is a top view of the throat-plate, showing the application of my sharpening-stone for the cutter. Fig. 2 is a cross'section of same on line :0 a". Fig. 3 is a perspective view of the throat-plate and cutter in operating position, and Fig. 4 is a sectional View showing a portion of Fig. 2.

A represents the throat-platewhich is provided with the feed-slot B, needle-hole O, and a. cutting-edge, G, for the knife or cutter H, which is provided with a cuttingedge, h, and a guiding-stem, II, which latter extends down below the said cuttingedge, and is guided in a notch, I in the throat-plate, by which its vertical reciprocations are perfectly guided. The cutting-edge h of the cutter H cuts against the stationary edge G of the throat-plate.

D is a small rectangular piece of-a sharpen= ing-stonc, preferably of a very fine grade of texture, and is guided in a slot or groove, D, in the throat-plate, and is held therein in any suitable manner-as, for instance, by screws 1 and the edge of said stone adjacent to the cutter is made slightly inclined, as at d, to correspond to the inclination of the cuttingedge of said cutter, as indicated in Fig. 4, so

that the vertical reciprocation of said cutter causes the cutting-edge to rub upon the said stone, keeping it sharp and in good cutting condition.

Hcretofore in machines of this class the cutting-edge h invariably lost its edge after being in use but a very limited time. My aim is to provide suitable sharpening devices by which, without materially altering the general construction of the trimming attachments for sewing-machines of this class, I am enabled to maintain the cutter in an operati'vely sharp condition through theapplication ot'the sharpening-stone, when applied in the manner hereinbefore set i'erth and shown.

As the edge (I of the sharpening-stone D becomes worn by the constant rubbing thereon of the inclined edge of the cutter II, it may be fed up toward the cutter to compensate for the wear thereof, thus insn ring a constantly-sharp cutting-edge of the blade without any care or watchfulness on the part of the operator.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a sewing-machine trimming attach ment, the combination, with a reciprocating trimming-knife having a guiding-stein and cutting-edge, of throat-plate having a cuttingedge thereon, against which said trimmingknife cuts, and a recess and a notch for said guiding-stem, and a sharpening-stone sup ported by the recess in said throat-plate and arranged in the path of the cutting-blade, so as to rub the edge thereof during its reciprocation, substantially as and for the purpose specified.

2. The combination of the throat-platc A, having notch F, cutting-edge G, and recess D, with sharpening-stone D and cutter H, having cuttingcdge h and. guiding-stem H, substantially as and for the purpose specified.

In testimony of which invention I hereunto set my hand.

- THUS. K. OBEB. 'Witnesses:

Fnixnors F. EASTLACK, Jn, ANGELO T. FREEDLEY. 

